Here is one of the greatest mysteries ever written, told not with action, but with dialog. Alan Grant of Scotland Yard, laid up in hospital after falling down a manhole chasing after some baddies, becomes interested in what happened to the "princes in the tower", supposedly murdered by their reviled father Richard III shortly before his death in battle. Tey makes a very good case for Richard's innocence in the matter and I highly recommend this book for lovers of historical puzzles. My online review is featured on this episode of The Mind Keep podcast: